Plasmon assisted transport through disordered array of quantum wires

– Phononless plasmon assisted transport through a long disordered array of finite length quantum wires is investigated analytically. Generically strong electron plasmon interaction in quantum wires results in a qualitative change of the temperature dependence of thermally activated resistance in comparison to phonon assisted transport. At high temperatures, the thermally activated resistance is determined by the Luttinger liquid interaction parameter of the wires. Hopping transport in a quasi-one-dimensional system formed by a parallel arrangement of conducting wires is of much relevance to a number of experimental setups, including quantum wire arrays in heterojunctions [1], carbon nanotube films [2], atomic wires on silicon surface [3], and stripe phases [4]. At finite length of constituent wires, such systems represent particular examples of granular arrays, where a one-dimensional wire plays the role of a grain. Considered as a granular array, the array of parallel quantum wires is rather peculiar because of the very long charge relaxation time in a one-dimensional wire. Due to this peculiarity, the theoretical description of thermally activated transport in arrays of long quantum wires requires taking into account the charge dynamics and treatment of the interactions beyond the capacitive model adopted in recent theoretical investigations of transport through disordered granular arrays [5]. In this letter we show that charge-density fluctuations (plasmons) in the array can act as the agent promoting thermally activated transport, thus providing the possibility for phononless inelastic transport. As the result of generically strong plasmon-electron coupling in a quantum wire, the features of plasmon and phonon assisted transport are qualitatively different. We provide a qualitative explanation of plasmon assisted transport, identify the transport regimes, where the features of plasmon and phonon assisted transport are either similar or substantially different, and derive analytic expressions for the temperature dependence of the thermally activated resistance for a special model of a strongly correlated disordered array of quantum wires. The model we formulate below is special, because it combines two seemingly incompatible features: i) it is strongly disordered for single electron transport; ii) it is much weaker disordered for propagation of plasmons.